Question

D. Answer the following questions in brief.
1.
The bulb in the circuit shown in figure does not glow. Why? Redraw the circuit
diagram by making the necessary changes in it, so that the bulb starts glowing.
Switch
Bulb
Battery
2. Name three practical devices based on the heating effect of current.
3. Write two special characteristics of the wire needed for making the element'
of an electric heater.
Give the meaning of the terms 'short circuiting' and 'overloading in an electric
circuit?
5.
Do you think an electromagnet can be used for separating plastic bags from a
garbage heap? Explain.
6. State
State any three applications of an electromagnet.
E. Answer the following questions.
1. The same amount of current flows through the connecting wires and the bulb
filament. However, it is only the filament that glows. Why?
2.
The brightness of light, emitted by a bulb, is observed to decrease when an
electric heater is connected in series with it. Suggest the likely reason for this
observation.
3. Suggest an experimental set up to illustrate the action of an electric fuse.
A novice electrician, while carrying out some repairs in Sumit's house, tried to
put a piece of tungsten wire in a 'fuse. Sumit's father, on noticing this, stopped
him from doing so. Give reasons as to why he did that.
5.
Draw a labelled diagram of an electric bell and explain its working.​

Answer 1

Answer:1) The bulb did not glow as the switch is not turned on which obstructs electric current to flow through it. Also, the battery in the figure has both terminals as positive. It should be one negative terminal and one positive terminal.

Redrawn diagram is also given.

2)Name three practical devices based on the heating effect of current. hope this helps. electric grill. electric space heater

3)1.  It should have a high boiling point.

2. It should very ductile .

5)No, electromagnets attract only magnetic substances. Plastic bags are non-magnetic in nature and are not attracted by an electromagnet. Hence, an electromagnet cannot be used for separating plastic bags from a garbage heap.

6)

1.The same amount of current flows through the connecting wires and the bulb filament however it is only the filament that glows why​ A wire connected to a bulb does not glow, whereas the filament of the bulb gilows when same current flows through them.

2.The voltage is divided into two parts so the available voltage for the bulb is less than 220 V. So, the brightness of light emitted from the bulb will decrease. The reason for this is that heater demands higher voltage so some of the voltage will be cut off from the bulb in order to provide full current to the heater because heater needs more current to work as compared to the bulb.  

3.Sumit's father stopped him from doing this because fuse wire is made up of metals having less melting point. Due to which whenever a slightly higher electric current flows through it, it breaks the wire and hence damage to electrical appliances is prevented. But tungsten on the other hand has a high melting point and allows the electric current to flow through it and damages electrical appliances  . It does not break the circuit.